[PATCH v1 0/2] Enable orphan-handling=warn for VDSO

[PATCH v1 0/2] Enable orphan-handling=warn for VDSO

[Joey Gouly]

Hi all,

This small series enables the orphan-handling linker flag for the VDSO.
This could catch subtle errors if features that use special sections are
introduced into the VDSO implementation.

Thanks,
Joey

Joey Gouly (2):
  arm64: vdso: put ELF related sections in the linker script
  arm64: vdso: enable orphan handling for VDSO

 arch/arm64/kernel/vdso/Makefile   | 8 +++++++-
 arch/arm64/kernel/vdso/vdso.lds.S | 5 +++++
 2 files changed, 12 insertions(+), 1 deletion(-)

-- 
2.17.1


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[PATCH v1 1/2] arm64: vdso: put ELF related sections in the linker script

[Joey Gouly]

These are the same sections as ELF_DETAILS in include/asm-generic/vmlinux.lds.h

Signed-off-by: Joey Gouly <joey.gouly@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Masahiro Yamada <masahiroy@kernel.org>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Kees Cook <keescook@chromium.org>
---
 arch/arm64/kernel/vdso/vdso.lds.S | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/arch/arm64/kernel/vdso/vdso.lds.S b/arch/arm64/kernel/vdso/vdso.lds.S
index a5e61e09ea92..e453e74e98f9 100644
--- a/arch/arm64/kernel/vdso/vdso.lds.S
+++ b/arch/arm64/kernel/vdso/vdso.lds.S
@@ -54,6 +54,11 @@ SECTIONS
 	_end = .;
 	PROVIDE(end = .);
 
+	.comment 0 : { *(.comment) }
+	.symtab 0 : { *(.symtab) }
+	.strtab 0 : { *(.strtab) }
+	.shstrtab 0 : { *(.shstrtab) }
+
 	/DISCARD/	: {
 		*(.data .data.* .gnu.linkonce.d.* .sdata*)
 		*(.bss .sbss .dynbss .dynsbss)
-- 
2.17.1


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Re: [PATCH v1 1/2] arm64: vdso: put ELF related sections in the linker script

[Kees Cook]

On Tue, Apr 05, 2022 at 05:02:45PM +0100, Joey Gouly wrote:
> These are the same sections as ELF_DETAILS in include/asm-generic/vmlinux.lds.h

Can include/asm-generic/vmlinux.lds.h be included to just use
ELF_DETAILS directly?

Outside of that, yeah, this series looks good. Thanks!

-Kees

> 
> Signed-off-by: Joey Gouly <joey.gouly@arm.com>
> Cc: Catalin Marinas <catalin.marinas@arm.com>
> Cc: Will Deacon <will@kernel.org>
> Cc: Masahiro Yamada <masahiroy@kernel.org>
> Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
> Cc: Kees Cook <keescook@chromium.org>
> ---
>  arch/arm64/kernel/vdso/vdso.lds.S | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/arch/arm64/kernel/vdso/vdso.lds.S b/arch/arm64/kernel/vdso/vdso.lds.S
> index a5e61e09ea92..e453e74e98f9 100644
> --- a/arch/arm64/kernel/vdso/vdso.lds.S
> +++ b/arch/arm64/kernel/vdso/vdso.lds.S
> @@ -54,6 +54,11 @@ SECTIONS
>  	_end = .;
>  	PROVIDE(end = .);
>  
> +	.comment 0 : { *(.comment) }
> +	.symtab 0 : { *(.symtab) }
> +	.strtab 0 : { *(.strtab) }
> +	.shstrtab 0 : { *(.shstrtab) }
> +
>  	/DISCARD/	: {
>  		*(.data .data.* .gnu.linkonce.d.* .sdata*)
>  		*(.bss .sbss .dynbss .dynsbss)
> -- 
> 2.17.1
> 

-- 
Kees Cook

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[PATCH v1 2/2] arm64: vdso: enable orphan handling for VDSO

[Joey Gouly]

Like vmlinux, enable orphan-handling for the VDSO. This can catch
subtle errors that might arise from unexpected sections being included.

Signed-off-by: Joey Gouly <joey.gouly@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Masahiro Yamada <masahiroy@kernel.org>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Kees Cook <keescook@chromium.org>
---
 arch/arm64/kernel/vdso/Makefile | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/kernel/vdso/Makefile b/arch/arm64/kernel/vdso/Makefile
index 172452f79e46..623d9ad2c717 100644
--- a/arch/arm64/kernel/vdso/Makefile
+++ b/arch/arm64/kernel/vdso/Makefile
@@ -24,7 +24,13 @@ btildflags-$(CONFIG_ARM64_BTI_KERNEL) += -z force-bti
 # routines, as x86 does (see 6f121e548f83 ("x86, vdso: Reimplement vdso.so
 # preparation in build-time C")).
 ldflags-y := -shared -soname=linux-vdso.so.1 --hash-style=sysv	\
-	     -Bsymbolic --build-id=sha1 -n $(btildflags-y) -T
+	     -Bsymbolic --build-id=sha1 -n $(btildflags-y)
+
+ifdef CONFIG_LD_ORPHAN_WARN
+  ldflags-y += --orphan-handling=warn
+endif
+
+ldflags-y += -T
 
 ccflags-y := -fno-common -fno-builtin -fno-stack-protector -ffixed-x18
 ccflags-y += -DDISABLE_BRANCH_PROFILING -DBUILD_VDSO
-- 
2.17.1


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